Data & CSV

Add CSV row numbers

Add a sequential identifier column without changing the original cells.

Your inputs

Your CSV data

UTF-8 CSV/TSV stays on this device. First row contains unique headings; maximum 25 MB, 50,000 rows and 200 columns. Fully empty rows are ignored.

Up to 25 MB per file, 50,000 data rows, 200 columns and 2 million data cells. Fully blank rows and columns are ignored before row, column and cell limits are checked. Individual tools may have smaller result or chart limits.

Or choose a CSV file

Column separator

New row-number heading

Starting number

Increment each row

Results update as you type. Larger files run when you press Update result.

Processed on your device

Your result

LOCAL & PRIVATE

Your result will appear here.

Your inputs stay in this browser. Nothing is uploaded or saved.

A clear answer. Here’s how.

Prepends a new column with start + zero-based input position × increment. Allows positive, zero or negative whole-number increments. The new heading must be non-empty and not already present. Original row order and cell strings are preserved; output must remain within 200 columns.

See a worked example

Worked example

A fixed demonstration, separate from the values you enter above.

Your CSV data

ID,Name,Department,Amount,Date
001,Ada,Design,120,2026-01-05
002,Sam,Writing,80,2026-01-06
003,Jo,Design,150,2026-01-07
004,Lee,Writing,,2026-01-08
005,Alex,Design,60,2026-01-09

Column separator

Comma

New row-number heading

Row

Starting number

Increment each row

Example result

Example result
Row	ID	Name	Department	Amount	Date
1	001	Ada	Design	120	2026-01-05
2	002	Sam	Writing	80	2026-01-06
3	003	Jo	Design	150	2026-01-07
4	004	Lee	Writing		2026-01-08
5	005	Alex	Design	60	2026-01-09